Virginia, Kentucky, Massachusetts, and Pennsylvania are each referred to as the "Commonwealth of..." It has no legal meaning anymore. as far as I know.
As to us joining you, we have that difference in allegiance that one side or the other would have to give up.
Oath to support and defend the U.S. Constitution regardless of the clowns in office.
I believe you swear an oath to the reigning monarch (does that have to be taken again upon a change?) regardless of the clowns in government.